A5047381766- Semiconductor materials and devices
- Ferroelectric and Negative Capacitance Devices
- Physics of Superconductivity and Magnetism
- Ferroelectric and Piezoelectric Materials
- Ion-surface interactions and analysis
- Integrated Circuits and Semiconductor Failure Analysis
- GaN-based semiconductor devices and materials
- Electronic and Structural Properties of Oxides
- Silicon and Solar Cell Technologies
- Metal and Thin Film Mechanics
- Quantum and electron transport phenomena
- Semiconductor Quantum Structures and Devices
- Earthquake and Tsunami Effects
- Plasma Diagnostics and Applications
- Advancements in Semiconductor Devices and Circuit Design
- Advanced Data Storage Technologies
- Magnetic properties of thin films
- ZnO doping and properties
- Semiconductor materials and interfaces
- Magnetic and transport properties of perovskites and related materials
- Radiation Effects in Electronics
- Magneto-Optical Properties and Applications
- Ga2O3 and related materials
- Electron and X-Ray Spectroscopy Techniques
- Acoustic Wave Resonator Technologies
Niigata University
2024
National Institute of Advanced Industrial Science and Technology
2013-2024
Kyushu Institute of Technology
2024
Nissin Kogyo (Japan)
2010-2023
Tokyo Institute of Technology
2015-2017
Sapporo Minami Hospital
2015
Iwate University
2000-2014
The University of Tokyo
1976-2012
Toshiba (Japan)
2009-2012
Kyoto University
1994-2011
In a system of thin alternating layers superconductors and insulators the equations describing static dynamic fluxon solutions are derived. The approach, represented by useful compact matrix form, is intended to describe systems fabricated for example niobium or niobium-nitride films; in limit ultrathin superconductor films it may give model motion layered high-Tc superconductors. Numerical examples current versus voltage curves be expected such an experiment presented.
We have investigated Josephson effects in stacks of both artificial and natural junctions. The measurements been performed on Nb/Al-${\mathrm{AlO}}_{\mathit{x}}$/Nb multilayers small single crystals ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{8}$. Both systems exhibit multiple branched I-V characteristics zero magnetic field. In finite fields coupling via currents flowing along the superconducting layers is essential, since are thinner than London penetration...
A ferroelectric memory field-effect transistor (FET) with a Pt-SrBi/sub 2/Ta/sub 2/O/sub 9/-Hf-Al-O-Si gate stack was fabricated and its electrical properties were characterized. The insulating layers successively deposited by laser ablation technique. Excellent data retention characteristics obtained. drain currents of on- off-states measured as function time, after /spl plusmn/6 V poling voltage applied to the electrode. current ratio more than 10/sup 6/ even 12 days. Moreover, 12/ cycles...
Thin films of multiferroic (Bi0.6Tb0.3La0.1)FeO3 were grown on Pt∕Ti∕SiO2∕Si substrate under various oxygen pressures by pulsed laser deposition technique. X-ray diffraction patterns show that the crystallinity thin film is improved with decreasing depositing pressure and at a lower 0.01torr exhibits single perovskite phase preferred (001) orientation. Leakage current as-deposited decreases pressure. Significantly, leakage can be reduced largely an annealing process 800°C flowing oxygen. The...
Characteristic velocities of the electromagnetic waves propagating in vertically stacked Josephson transmission are theoretically discussed. An equation for solving n an Josephson-junction stack is derived. The solutions two- and threefold stacks especially focused on. Furthermore, under assumption that all parameters layers equal, analytic a generic N-fold presented. three-junction by Nb-Al-${\mathrm{AlO}}_{\mathit{x}}$-Nb systems experimentally obtained measuring cavity resonance (Fiske...
Self-aligned-gate Pt/SrBi 2 Ta O 9 /HfAlO/Si metal/ferroelectric/insulator/semiconductor (MFIS) field-effect transistors (FETs) were fabricated. Drain current ( I d ) versus gate voltage curves of the MFIS FETs showed almost same steepness as that a non-self-aligned-gate Pt/HfAlO/Si metal/insulator/semiconductor FET. Long retention times with large on- and off-state ratios obtained for FETs. The more than 33 days an ratio over 10 5 demonstrated self-aligned-gate FET 2-µm-long 80-µm-wide...
The exciton-localization effect and quantum-confine Stark (QCSE) on the performance of InGaN/GaN-based light-emitting diodes (LEDs) have been investigated with regard to indium mole fraction well thickness by means temperature-dependent excitation-power-dependent photoluminescence measurements. can be enhanced increasing or but up 2.5 nm. QCSE is monotonically concentration thickness. output power LED increased effect; however, has much stronger influence LEDs than effect, which should taken...
By introducing the AlInGaN/AlGaN quaternary system as an active region, we fabricated UV light-emitting diode (LED) with emission wavelength of 348 nm. The optical power is 1 mW at injection current 50 mA under a bare-chip geometry, which highest report among UV–LEDs around 350 nm grown on sapphire substrate. It means that such LEDs high enough to be used in practical application. In contrast it, similar UV–LED based GaN/AlGaN region has been also grown, whose less than AlInGaN/AlGaN-based...
Today NAND Flash memory is used for data and code storage in digital cameras, USB devices, cell phones, camcorders, solid-state disk drives. Figure 13.6.1 shows the memory-density trend since 2003. To satisfy market demand lower cost per bit higher density nonvolatile memory, addition to technology scaling, 2b/cell MLC was introduced. Recently, flash memories with more than [1,2] have been reported.
We prepared SrBi2Ta2O9(SBT) ferroelectric thin films on SiO2/Si and MgO buffered substrates using laser ablation, in situ annealing postannealing, observed retention time longer than 7 days. On substrates, only the samples annealed at 800 °C occasionally exhibited good memory properties. successful probability for finding measuring dots increased largely even while postannealing temperature was as low 650 °C; their typical window 3.1 V over days without serious degradation. The buffer layer...
We report on numerical simulations of 10- and 19-layer stacked Josephson junctions. Simulations are performed using the experimentally feasible parameters for Nb/Al–AlOx/Nb With an appropriate choice such as magnetic field coupling, current–voltage curves N-layer stacks systematically indicate in-phase locking among inner N−2 The simulation results suggest that multilayer junctions very promising submillimeter-band high-power oscillators.
A metal-ferroelectric-insulator-semiconductor (MFIS) field-effect-transistor (FET) composed of a Pt/SrBi2Ta2O9(SBT)/Hf-Al-O/Si stack with long data retention over 106 s was fabricated. The poling voltages to obtain the were ±6 V. memory window in drain current vs gate voltage (Id–Vg) curve increased monotonically increasing scan-voltage amplitude (Vscan) up Vscan=6 This behavior indicates that device operation is based on unsaturated ferroelectric polarization switching. direct...
Temperature dependence of electrical properties is studied statistically from 24 p-channel Pt∕SrBi2Ta2O9∕Hf–Al–O∕Si field-effect transistors up to 85°C. They show consistent and the distribution threshold voltage narrow. The memory window decreases 1.40to1.15V as temperature increases 27to85°C. Retention characterized at zero bias voltage. on-/off-state drain current ratios are above 105 27°C nearly 104 85°C after more than 105s measurement, respectively. These results promising for future...